The present invention relates to a device for compensating masses, e.g., applicable to a rotary boring head, and particularly to a device for compensating masses useful in rotary boring heads used for finishing high precision bores. The present invention also relates to a rotary boring head incorporating the mass compensating device.
In the prior art, boring heads are known of the type that are fixed on a machine tool main spindle such that there is only one single position under which the center of gravity of the movable sliding element of the tool holder and the cutting tool itself coincide with the rotating axis of the boring head.
It is also known in the prior art that with the displacement of the movable parts of the boring head, the center of gravity of the boring head changes its balancing position, which is normally located over the rotating axis, leading to the unbalancing of the boring head. This unbalancing action increases even more as a sliding element in the boring head is radially displaced to the outside in relation to the rotating axis.
Owing to vibrations generated by the lack of balancing masses in the boring head, the harm caused to the precision and finishing of bores during machining have led to the addition of balancing devices to the boring heads.
In addition, since the bore precision is micrometric and rotation of current boring heads reaches extremely high levels, any unbalancing, even if only of a minute increment, leads to a quality loss of the machining job, because in these cases very close tolerances in the order of thousandths of a millimeter are under consideration.
In the prior art, an attempt has been made to overcome the unbalancing condition through the action of counterweights for mass displacement. However, it is a disadvantage that the known embodiments of such counterweights do not enable the rotary boring head to attain sufficiently high levels of graduated balancing operation adequate for each situation.